| nucleus paraventricularis | A triangular group of large magnocellular neurons in the periventricular zone of the anterior half of the hypothalamus. The cells of the nucleus are similar to those of the supraoptic nucleus; the axons of about 20% of their number join in the formation of the supraopticohypophysial tract and are functionally associated with the posterior lobe of the hypophysis; they project fibres to the brainstem nuclei (dorsal motor nucleus and solitary nucleus) and to the intermediolateral cell column of the spinal cord at thoracic, lumbar, and spinal levels; similar descending autonomic fibres arise from the lateral and posterior hypothalamic nuclei. Synonym: nucleus paraventricularis, filiform nucleus, nucleus filiformis. (05 Mar 2000) |
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| nucleus preopticus lateralis | A vaguely defined group of nerve cells in the lateral zone of the preoptic region. Synonym: nucleus preopticus lateralis. (05 Mar 2000) |
| nucleus preopticus medialis | A group of nerve cells forming the medial zone of the preoptic region. Synonym: nucleus preopticus medialis. (05 Mar 2000) |
| nucleus pulposus | The soft fibrocartilage central portion of the intervertebral disk; regarded as a derivative of the notochord. Synonym: gelatinous nucleus, nucleus gelatinosus, vertebral pulp. (05 Mar 2000) |
| nucleus pyramidalis | An obsolete term for nucleus olivaris accessorius medialis. (05 Mar 2000) |
| nucleus reticularis thalami | A sheet of fairly large neurons covering the lateral, ventral, and rostral surfaces of the thalamus; its reticular appearance is caused by the numerous fascicles of the thalamic peduncles which traverse the nucleus The nucleus receives numerous fibres from the cerebral cortex but it has no cortical projection. Synonym: nucleus reticularis thalami. (05 Mar 2000) |
| nucleus ruber | A distinctive oval nucleus (pink in fresh specimens because of an iron-containing pigment in many of the cells) centrally placed in the upper mesencephalic reticular formation. It receives fibres from the deep cerebellar nuclei and cerebral cortex and projects fibres to the cerebellum, brainstem, spinal cord, and probably to the thalamus. The nucleus is divided into two regions: pars magnocellularis and pars parvocellularis. (12 Dec 1998) |
| nucleus salivatorius inferior | A group of preganglionic parasympathetic motor neurons located in the reticular formation of the medulla oblongata dorsal to the nucleus ambiguus; its axons leave the brain with the glossopharyngeal nerve and govern secretion from the parotid gland by the intermediary of the ganglion oticum; cells of the inferior and superior nucleus are scattered and overlapping in lateral regions of the reticular formation. Synonym: nucleus salivatorius inferior, inferior salivary nucleus. (05 Mar 2000) |
| nucleus salivatorius superior | A group of preganglionic parasympathetic motor neurons situated rostral and lateral to the inferior salivatory nucleus; it governs secretion of the lacrimal, sublingual, and submaxillary glands by way of the facial nerve and the sphenopalatine and submandibular ganglia. Synonym: nucleus salivatorius superior, superior salivary nucleus. (05 Mar 2000) |
| nucleus sensorius principalis nervi trigemini | <anatomy, nerve> The term commonly used to designate the nucleus pontis nervi trigeminalis; located in pons lateral to the motor trigeminal nucleus; receives primary sensory (touch and pressure) input via the trigeminal nerve, projects to ventral posteromedial nucleus of thalamus. Synonym: nucleus sensorius principalis nervi trigemini, nucleus sensorius superior nervi trigemini, principal sensory nucleus of the trigeminus. (05 Mar 2000) |
| nucleus sensorius superior nervi trigemini | <anatomy, nerve> The term commonly used to designate the nucleus pontis nervi trigeminalis; located in pons lateral to the motor trigeminal nucleus; receives primary sensory (touch and pressure) input via the trigeminal nerve, projects to ventral posteromedial nucleus of thalamus. Synonym: nucleus sensorius principalis nervi trigemini, nucleus sensorius superior nervi trigemini, principal sensory nucleus of the trigeminus. (05 Mar 2000) |
| nucleus spinalis nervi accessorii | spinal nucleus of accessory nerve |
| nucleus subthalamicus | A circumscript nucleus, shaped like a biconvex lens, located in the ventral part of the subthalamus on the dorsal surface of the peduncular part of the internal capsule immediately rostral to the substantia nigra. The nucleus receives a massive topographic projection from the lateral segment of the globus pallidus, and a somatopically organised projection from the ipsilateral motor cortex; a smaller bundle of afferents from the centromedian nucleus of the thalamus terminate in the rostral part of the nucleus The subthalamic nucleus projects to both pallidal segments, to the pars reticulata of the substantia nigra, and in a small way to the ipsilateral pedunculopontine nucleus. Synonym: nucleus subthalamicus, corpus luysi, Luys' body, nucleus of Luys. (05 Mar 2000) |
| nucleus suprachiasmatica | Small nucleus located dorsal to the optic chiasm; receives input from retina, influences hypothalamic neuroendocrine function; closely associated with regulation of circadian rhythmicity. (05 Mar 2000) |
| nucleus supraopticus hypothalami | A large-celled neurosecretory nucleus in the hypothalamus, located over the lateral border of the optic tract, from which the supraopticohypophysial tract arises; its neurons produce and transport vasopressin released into the general circulation from the axon terminals in the supraopticohypophysial tract. Synonym: nucleus supraopticus hypothalami, supraoptic nucleus. (05 Mar 2000) |